1. Technical Field
The technology disclosed herein relates to a lens barrel that supports an optical system.
2. Background Information
There are known lens barrels that support an optical system with which the focal distance can be varied. For example, the lens barrel disclosed in Japanese Laid-Open Patent Application 2007-219304 comprises a first moving cam ring in which a cam groove is formed, and a first group lens barrel that supports a first lens group. The first group lens barrel has a follower pin that engages in the cam groove. With this lens barrel, the first moving cam ring and the first group lens barrel allow the first lens group to be moved in the optical axis direction with respect to the first moving cam ring.
A gear for driving with a motor or the like is formed on the outer periphery of a frame used in this type of lens barrel. Also, a plurality of cam followers are often formed on the frame to which the gear is provided.
However, when a gear and a plurality of cam followers are provided to the same frame, the gear is disposed between the cam followers, but with this layout, the length of the gear is limited by the cam followers, so the rotational angle of the frame cannot be increased. When increasing the zoom ratio of the lens barrel is taken into account, it is preferable to have a larger rotational angle of the frame.
It is an object of the technology disclosed herein to provide a lens barrel with which the zoom ratio can be increased.